8.16 day17

package

Before we talked about the module, but if a module's function too, it would seem more trouble. If it directly into multiple files, will not only change the way imported, and users will have caused no small trouble, after all, different functions in different files, it still fails to find a user a? This time the package appeared usage

What is the package? After the package is a module divided into multiple files, and import the same manner, with the packages or from m1 import f1, the user feels no change

Package is a folder, but which must have __init__ this file in nature. In other words, __ init__ make an ordinary folder into a bag, guide package is the guide inti

The first way to use

from m1 import f1

from m1 import *  # 运行init这个文件，创建一个init这个名称空间，然后把inti内的变量丢入 init 这个名称空间内

f1()  # 导包以执行文件的环境变量为基准
f2()
f3()
f4()
# import sys
# print(sys.path)

import requests


from m1 import f1()
from m1 import f7

f7()

Although this method is feasible but not recommended

Package guide is introduced init

Package of environmental variables executable file as a reference, init package can only start importing from the package name

Relative import: (only in the package)

Is the current directory
.. the parent directory

time module

Timestamp

print(time.time())      # 1565958257.9459026

This is the time in 1970 to the present

But this time the child will see a lot of trouble

Formatting time

#                    year month day X
print(time.strftime('%Y_%m_%d %X'))  # 2019_08_16 10:26:36

This more comfortable

Structured time

print(time.localtime())  # 当地时间（中国）
print(time.gmtime())  # 标准时间

Three kinds of time format conversion

# 结构化时间转格式化时间
print(time.strftime('%Y-%m-%d %X', time.localtime()))
# 格式化时间转结构化时间
print(time.strptime('2019-08-16 10:30:44', '%Y-%m-%d %X'))

# 结构化时间转时间戳
print(time.mktime(time.localtime()))
# 时间戳转结构化时间
print(time.localtime(time.time()))

Emphasis

time.time()
time.sleep(2)

datetime module

import datetime


print(datetime.datetime.now())  # 打印时间


now = datetime.datetime.now()

print(now+datetime.timedelta(3))  # 默认+3天

print(now+datetime.timedelta(hours=3))  # 3小时
print(now+datetime.timedelta(minutes=3))  # 3分钟


print(now.replace(year=1900))

os module

mport os


print(os.getcwd()) # 获取当前文件目录

os.mkdir('m2') # 创建一个文件夹
os.rmdir('m2')  # 删除文件夹

res = os.listdir(r'D:\上海Python11期视频\python11期视频\day 17')  # 列出所有文件
print(res)

os.rename('test.py','test1.py')
os.remove('test1.py')

__file__ only pycharm was provided, python itself does not support

print('os.path.abspath(__file__):',os.path.abspath(__file__))  # 支持不同的平台(windows,ios,andirod,linux,unix)

rint(os.path.exists('01 包.py'))  # 文件不存在False，存在True

print(os.path.exists('01 包.py'))  # 文件不存在False，存在True


print(os.path.isfile('01 包.py')) # 是否为文件
print(os.path.isdir('01 包.py')) # 是否为文件夹

# ********（经常使用）
# 支持不同的平台(windows,ios,andirod,linux,unix)
res = os.path.join(r'D:\上海Python11期视频\python11期视频\day 17\m1\bbb','m5.py') # 拼接文件路径
res = os.path.join(r'D:\上海Python11期视频\python11期视频\day 17\m1\bbb','m5','test.py') # 拼接文件路径
# print(r'D:\上海Python11期视频\python11期视频\day 17\m1\bb'+'\m5.py')
print(res)

# ******* （经常使用）
print(os.path.abspath(__file__))
print(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

import os
g = os.walk(r'D:\上海Python11期视频\python11期视频\day 17')  # 返回三个值，第一个值是路径；第二个值是路径下的文件夹，第三个值是路径下的文件
for i in g:
    print(i)

sys module

#sys模块： 与Python解释器交互
import  sys


# print(sys.path)   # 路径


print(sys.argv)  # 接收参数（用cmd执行文件时运行才有效）


print(sys.modules)

json

# json模块：

# 用python写了一个程序，用java写了一门程序，这两个程序需要数据之间交流，规定了一种多种语言通用的数据类型，json串


# 序列化：从python的字典（最常用）变成json串， dump


# 反序列化：从json串变成python的字典（最常用），load


import json

dic = {'a': 1, 'b': 'abc', 'c': None}
data = json.dumps(dic)  # 序列化到内存中
print(data,type(data))  # 单引号全部变成双引号
data = json.loads(data)  # 从内存中获取json串
print(data,type(data))

with open('test.json','w',encoding='utf8') as fw:
    json.dump(dic,fw)

with open(f'{"test"}.json','r',encoding='utf8') as fr:
    data = json.load(fr)
    print(data)

pickle module

But when the method is similar to json be deserialized when the pickle executable file export function, can only export the file to perform the function of the same name, because the pickle store only function is to store the address, and not stored value of the function

# 文件1
def func():
    x = 3
    print(x)

import pickle
with open('test.pkl','wb') as fw:
    pickle.dump(func,fw)


# 文件2
with open('test.pkl', 'rb') as fr:
    data = pickle.load(fr)
    data()
    print(data)

As the above code, if an error is reported to run the file 2, file 2 because there are no defined function FUNC (), also defined even only shows the functions defined in the file

In other words, pickle deserialization function is useless

hashlib module

Generally used for secret password

import hashlib

m = hashlib.md5()  # 固定的写法
m.update(b'123456')
# m.update(b'456')
print(m.hexdigest())

After the hash features:

1. It becomes a fixed character string
2. The same result as the hash string
3. Superposition

hmac module

import hmac

m = hmac.new(b'abc')  # 加盐
m.update(b'123456')
# m.update(b'456')
print(m.hexdigest())

Hashlib similar method, but the administrator can set a key value, the more difficult to decipher

logging module

General logging modules are applied template, not explained in detail here

```
mport logging

logging.debug ( 'debugging') # 10

logging.info ( 'normal') with which a # 20 #

logging.critical ( 'serious error') # 30

logging.error ( 'error') # 40

logging.warning('警告') # 50

The default can output more than 30

v2 log information recorded in the file which

logging.basicConfig(filename='access.log',

format='%(asctime)s - %(name)s - %(levelname)s -%(module)s: %(message)s',

datefmt='%Y-%m-%d %H:%M:%S %p',

level=10)

logging.debug ( 'debugging') # 10

logging.info ( "normal information") # 20

logging.warning ( 'warning') # 30

logging.error ( 'error message') # 40

logging.critical ( 'serious error') # 50

1. Create a logger objects

logger = logging.getLogger('hyc')

2. Generate format

formmater1 = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s -%(module)s: %(message)s',
datefmt='%Y-%m-%d %H:%M:%S %p',)
formmater2 = logging.Formatter('%(asctime)s : %(message)s',
datefmt='%Y-%m-%d %H:%M:%S %p',)
formmater3 = logging.Formatter('%(name)s %(message)s',)

3. Create a file object

h1 = logging.FileHandler('h1.log')
h2 = logging.FileHandler('h2.log')
sm = logging.StreamHandler()

4. Bind file format

h1.setFormatter (formmater1)
h2.setFormatter (formmater2)
sm.setFormatter (formmater3)

5. Binding documents

logger.addHandler(h1)
logger.addHandler(h2)
logger.addHandler(sm)

6. Control Level

logger.level = 50

7. Use

logger.debug ( 'debugging') # 10
logger.info ( 'normal information') # 20 is
logger.warning ( 'warning') # 30
logger.error ( 'error message') # 40
logger.critical ( 'serious error message ') # 50